Shape memory device with temperature-dependent deflectable segment and methods of positioning a shape memory device within a bone structure

ABSTRACT

A system for augmenting a bone structure. A shape memory device includes a deflectable distal segment including temperature-dependent memory metal material. The shape memory device is slidably received within a guide cannula. The deflectable distal segment may include a substantially longitudinally straightened form, such as when subjected to a force from the guide cannula. The deflectable distal segment forms a first deflected shape having a first bend away from said straight longitudinal axis at a first elevated temperature greater than an initial temperature, and forms a second deflected shape having a second bend away from said straight longitudinal axis at a second elevated temperature greater than said first elevated temperature. The shape memory device may create voids within the bone structure with the deflectable distal segment at the first and/or second bends. Methods for positioning a shape memory device within a bone structure are also disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of co-pending U.S. application Ser.No. 15/076,221, filed Mar. 21, 2016, which is a continuation of U.S.application Ser. No. 14/223,064, filed Mar. 24, 2014 (now issued as U.S.Pat. No. 9,358,059), which is a continuation of U.S. application Ser.No. 13/483,899, filed May 30, 2012 (now issued as U.S. Pat. No.8,690,884), which is a continuation-in-part of U.S. patent applicationSer. No. 12/633,358, filed Dec. 8, 2009 (now issued as U.S. Pat. No.8,529,576), which is a divisional of U.S. application Ser. No.11/704,139, filed Feb. 8, 2007 (now issued as U.S. Pat. No. 7,799,035),which is a continuation-in-part of U.S. application Ser. No. 11/282,102,filed Nov. 11, 2005 (now issued as U.S. Pat. No. 7,713,273), each ofwhich is incorporated by reference herein in its entirety, and to whichpriority is claimed.

TECHNICAL FIELD

The present invention relates to devices and methods for stabilizingbone structures. More particularly, it relates to systems and methodsfor delivering a curable, stabilizing material into a bone structure.

BACKGROUND

Surgical intervention at damaged or compromised bone sites has provenhighly beneficial for patients, for example patients with back painassociated with vertebral damage.

Bones of the human skeletal system include mineralized tissue that cangenerally be categorized into two morphological groups: “cortical” boneand “cancellous” bone. Outer walls of all bones are composed of corticalbone, which has a dense, compact bone structure characterized by amicroscopic porosity. Cancellous or “trabecular” bone forms the interiorstructure of bones. Cancellous bone is composed of a lattice ofinterconnected slender rods and plates known by the term “trabeculae.”

During certain bone procedures, cancellous bone is supplemented by aninjection of a palliative (or curative) material employed to stabilizethe trabeculae. For example, superior and inferior vertebrae in thespine can be beneficially stabilized by the injection of an appropriate,curable material (e.g., PMMA or other bone cement). In other procedures,percutaneous injection of stabilization material into vertebralcompression fractures by, for example, transpedicular or parapedicularapproaches, has proven beneficial in relieving pain and stabilizingdamaged bone sites. Other skeletal bones (e.g., the femur) can betreated in a similar fashion. In any regard, bone in general, andcancellous bone in particular, can be strengthened and stabilized by apalliative injection of bone-compatible material.

The conventional technique for delivering the bone stabilizing materialentails employment of a straight access device or cannula that bores (orotherwise cuts) through the cortical bone to gain access to thecancellous bone site. Bone stabilization material is then driven throughthe cannula to fill a portion of the cancellous bone at the bone site.To minimize invasiveness of the procedure, the cannula is typically asmall diameter needle.

With the above in mind, because the needle cannula interacts with thecancellous bone and other soft tissue structures, an inherent riskexists that following initial insertion, the needle cannula might coreor puncture other tissue and/or the bone mass being repaired (at alocation apart from the insertion site). Thus, during percutaneousvertebroplasty, great care must be taken to avoid puncturing, coring, orotherwise rupturing the vertebral body. Similar post-insertion coringconcerns arise in other interior bone repair procedures. Along thesesame lines, to minimize trauma and time required to complete theprocedure, it is desirable that only a single bone site insertion beperformed. Unfortunately, for many procedures, the surgical site inquestion cannot be fully accessed using a conventional, straight needlecannula. For example, with vertebroplasty, the confined nature of theinner vertebral body oftentimes requires two or more insertions with thestraight needle cannula at different vertebral approach locations(“bipedicular” technique). It would be desirable to provide a system fordelivering bone stabilizing material that can more readily adapt to theanatomical requirements of a particular delivery site, for example asystem capable of promoting unipedicular vertebroplasty.

Certain instruments utilize a curved needle to deliver bone stabilizingmaterial as part of vertebroplasty or similar procedure. The curvedneedle purportedly enhances a surgeon's ability to locate and inject thestabilizing material at a desired site. Similar to a conventionalstraight needle cannula, the curved needle dispenses the curablematerial through a single, axial opening at the distal-most tip.However, the curved needle is used in combination with an outer cannulathat assists in generally establishing access to the bone site as wellas facilitating percutaneous delivery of the needle to the delivery site(within bone) in a desired fashion. More particularly, the outer cannulafirst gains access to the bone site, followed by distal sliding of theneedle through the outer cannula. After the needle's tip extends distala distal end of the outer cannula, the needle tip is “exposed” relativeto the bone site. To avoid coring, and thus potentially damaging, tissuewhen inserting the needle's distal tip into the bone site, an additionalwire component is required, coaxially disposed within the needle anddistally extending from the distal tip. The inner wire “protects” tissueor other bodily structures from traumatically contacting the distal tipof the needle as the tip is being positioned. The coaxial wire must beremoved prior to infusing the bone stabilizing material through theneedle.

Further, the needle can only dispense the stabilizing material throughthe axial opening at the distal tip of the needle, perhaps impeding asurgeon's ability to infuse all desired areas and/or requiring anadditional procedural step of “backing” the needle tip away from thedesired delivery site. Also, because the needle tip, and thus the axialopening, is likely at or facing the bone defect (e.g., fracture in thevertebral body) being repaired, the stabilizing material may be injecteddirectly at the defect, giving rise to a distinct possibility that thestabilizing material will forcibly progress through and outwardly fromthe defect. This is clearly undesirable. The issues and concernsdescribed above in the context of percutaneous vertebroplasty can alsoarise in similar surgical procedures at other bone sites.

The injection of palliative materials into damaged or compromised bonesites has proven highly beneficial for patients. However, the knownaccess and infusion techniques necessitate multiple needle sticks and/orrisk coring bone or tissue. Also, curved needles may suffer stressand/or binding within the lumen of guide cannulas and/or may include apre-set curve that does not provide for desired access to a targetedinjection site. Providing many different needles with differentcurvatures adds medical expense borne by patients and/or insurers, andthe need to exchange a needle for one with a different curvatureincreases procedure time (which may, for example, add patient time underanesthesia, increase cost for operating suite time usage). Therefore, aneed exists for an improved device and system for delivering stabilizingmaterial to damaged or compromised bone sites.

BRIEF SUMMARY

Embodiments disclosed herein may include a delivery cannula providing anon-traumatic, blunt distal end that minimizes the risks of coringtissue or puncturing bone or tissue during intraosseous procedureswithout requiring additional components (such as separate wire). Certainembodiments relate to vertebroplasty systems including guide cannula,delivery cannula, which may be embodied as a needle and that may beformed of or at least include a memory metal, where the memory metal isconfigured to be generally straight at ambient temperature and to bemanipulable to at least a first curve at a first higher selectedtemperature and a second curve at a second higher selected temperature.Certain embodiments may relate to a delivery cannula defining at leastone side orifice adjacent to a blunt distal end, where the orifice(s)permit a radial infusion of a curable material at a site within boneeven in the case where the distal end is in contact with bone and/ortissue. Thus, a palliative bone procedure can be accomplished withreduced operating room time and with fewer approaches of surgicalinstruments to the bone site. For example, unipedicular vertebroplastymay readily be accomplished. Further, virtually any area within thesurgical site may be accessible with less time and effort than would berequired with one or more needles having only a single pre-set curve.Also, the distal end of the delivery cannula can be placed as close asdesired to a particular anatomical feature of the surgical site (e.g., abone fracture) without fear that subsequently delivered material willforcibly progress into or through that feature. It should be appreciatedthat the present embodiments are readily adaptable within the art to beused in other bone augmentation procedures.

Some aspects of the presently disclosed embodiments may relate to adelivery cannula device for delivering a curable material into bone. Thedevice includes a delivery cannula and a hub forming a fluid port. Thedelivery cannula defines a proximal end, a deflectable segment includinga memory metal material, a distal end, a lumen, and at least one sideorifice. The proximal end is axially open to the lumen. The deflectablesegment is formed opposite the proximal end and terminates at the distalend that is otherwise axially closed. Further, the distal end has ablunt tip. The lumen extends from the proximal end and is fluidlyconnected to the side orifice(s). To this end, the side orifice(s) isformed adjacent to, and proximally space from, the distal end. Finally,the deflectable segment including a memory metal material may beactuated by predetermined application of a selected heat energy to format least a first curved shape and a second curved shape in longitudinalextension as it has a temperature-dependent multi-state curvature shapememory characteristic. With this configuration, the deflectable segmentbegins in a substantially straightened shape at ambient temperature andwill assume the first, second, and/or other curved shape upon provisionof heat energy to provide a corresponding temperature. The hub isfluidly coupled to the proximal end of the delivery catheter. With thisconstruction and during use, the distal end will not damage or coretissue when inserted into a delivery site within bone due to the blunttip. Further, the side orifice(s) afford the ability to inject a curablematerial regardless of whether the distal end is lodged against bodilymaterial, and can achieve more thorough dispensing.

Other aspects of the presently-disclosed embodiments may relate to anintraosseous, curable material delivery system for delivering a curablematerial, such as bone cement, to a delivery site within bone. Thesystem includes the delivery cannula and hub as described in theprevious paragraph, along with a guide cannula. The delivery cannula andthe guide cannula are sized such that the delivery cannula is slidablewithin the guide cannula. To this end, the deflectable segment isconfigured to maintain a substantially straight-line shape when insertedwithin the cannula and be actuatable to the first, second, and/orfurther curved shapes when extended distal the guide cannula fordelivery of the curable material and heated to corresponding first,second, and/or further temperatures. In one embodiment, the guidecannula and the delivery cannula may be sized to perform avertebroplasty procedure.

Yet other aspects of the presently disclosed embodiments may relate tomethods of stabilizing a bone structure of a human patient. The methodincludes providing a delivery cannula as previously described. A distaltip of a guide cannula is located within the bone structure. Thedelivery cannula is inserted within the guide cannula. In this regard,the deflectable segment begins in a substantially straightened shapewithin the guide cannula at a typical ambient temperature (definedherein as being at or below patient body temperature and generallywithin a range typical for a hospital operating room or similarenvironment, e.g., about 15° C. to about 38° C., preferably about 20° C.to about 23° C.). The delivery cannula is distally advanced relative tothe guide cannula such that the distal end and at least a portion of thedeflectable segment of the delivery cannula projects distal the distaltip of the guide cannula. To this end, the portion of the deflectablesegment distal the distal tip of the guide cannula may be actuated to aselected, temperature-dependent one of two or more curved shapes byproviding heat energy to establish a cannula temperature correspondingto the desired curvature. The distal end of the delivery cannula ispositioned adjacent a desired delivery site within the bone structure. Acurable material is injected into the lumen. The injected curablematerial is delivered to the delivery site via the side orifice(s).After it has been delivered, the curable material is allowed to cure soas to stabilize the bone structure. In one embodiment, the methodfurther includes rotating the delivery cannula relative to the guidecannula so as to alter a spatial position of the side orifice(s), thusaffording the ability to inject the curable material in differentplanes.

Still another aspect of the presently disclosed embodiments may relateto methods of injecting curable material to a delivery site within abone structure. The methods may include steps of providing a deliverycannula having an open, proximal end, a deflectable segment opposite theproximal end having a distal end, and a lumen extending from theproximal end. The deflectable segment has a shape memory characteristicand may be heat-actuated to assume a first, second, and/or furthercurved shape in longitudinal extension. The method may also include astep of locating a distal tip of a guide cannula within the bonestructure. The method may further include a step of inserting thedelivery cannula within the guide cannula, when the deflectable segmentis in a default substantially straightened shape within the guidecannula, and distally advancing the delivery cannula such that thedistal end and at least a portion of the deflectable segment projectsdistal the distal tip. The portion of the deflectable segment distal thedistal tip then may be heated to a selected temperature corresponding toa desired curve. The method may also include a step of manipulating thedelivery cannula such that at least a portion of the deflectable segment(when straight, and/or when curved) creates one or more voids in softbody tissue within the bone structure. The method may also include astep of delivering the curable material to the delivery site wherein thecurable material is delivered to the one or more voids in the soft bodytissue created by the deflectable segment.

Yet another aspect of the presently disclosed embodiments may relate toa method of injecting curable material to a delivery site within a bonestructure. The method includes the step of providing a delivery cannulahaving an open, proximal end, a deflectable segment opposite theproximal end having a distal end and a lumen extending from the proximalend. The deflectable segment has a shape memory characteristic and will,when heated to a corresponding selected temperature assume a first,second, and/or further curved shape in longitudinal extension. In themethod, the distal tip of a guide cannula may be located within the bonestructure. The delivery cannula is inserted within the guide cannula,where the deflectable segment is, at an ambient temperature, in asubstantially straightened shape within the guide cannula. The deliverycannula is distally advanced such that the distal end and at least aportion of the deflectable segment projects distal the distal tip,whereafter the portion of the deflectable segment distal the distal tipmay assume the first, second, and/or further curved shape uponapplication of heat energy to provide a corresponding temperature. Thedistal end is positioned distally adjacent a first region within thedelivery site. The curable material is then delivered to the firstregion within the delivery site. The distal end is then positionedadjacent a second region within the delivery site and curable materialis delivered to the second region within the delivery site. The secondsite may be accessed using the same cannula curvature as the first site,or the cannula may be heated to a different temperature corresponding toa different curvature to access a different second region.

Yet another aspect of the presently disclosed embodiments may relate toa cannula device for delivering a curable material, such as bone cement,into bone as part of a curable material delivery system. The deviceincludes a delivery cannula preloaded with bone cement, with the cannulaincluding an open, proximal end, a deflectable segment opposite theproximal end and terminating in a closed distal end. The device alsoincludes a lumen extending from the proximal end to at least one sideorifice formed adjacent to, and proximally spaced from, the distal end.The deflectable segment forms a curved shape in longitudinal extensionafter being heated, as it has a shape memory characteristic such that itis configured to assume a longitudinally, substantially straightenedform when at ambient temperature and at least two curved shapes, eachcorresponding to a different selected higher temperature.

In yet another aspect some presently disclosed embodiments relate tomethods of injecting curable material within a bone structure, somemethod comprising: providing a delivery cannula defining: an open,proximal end, a distal segment opposite the proximal end having a distalend, a lumen extending from the proximal end; locating a distal tip of aguide cannula within the bone structure; inserting the delivery cannulawithin the guide cannula; distally advancing the delivery cannula suchthat the distal end projects distal of the distal guide cannula tip;heating the delivery cannula to a first temperature to actuate it to afirst selected curvature; positioning the distal end distally adjacent afirst region within the delivery site; delivering the curable materialto the first region within the delivery site; positioning the distal enddistally adjacent a second region within the delivery site withoutremoving the guide cannula from the bone structure; delivering thecurable material to the second region within the delivery site; anddelivering the curable material to a third region within the deliverysite between and connecting the first and second regions. The method mayfurther include heating the delivery cannula to a second temperature toactuate it to a second selected curvature before or after positioningthe distal end distally adjacent the second region; and, if after, mayprovide for accessing the third region within the delivery site.

Yet another aspect of the presently disclosed embodiments may relate toa method of injecting curable material within a bone structure, themethod comprising: providing a delivery cannula defining: an openproximal end, a distal segment opposite the proximal end having a distalend, a lumen extending from the proximal end; locating a distal tip of aguide cannula within the bone structure; inserting the delivery cannulawithin the guide cannula; distally advancing the delivery cannula suchthat the distal end projects distal of the distal tip; heating thedelivery cannula to a first temperature to actuate it to a firstselected curvature; positioning the distal end distally adjacent a firstregion within the delivery site; delivering the curable material to thefirst region within the delivery site; positioning the distal enddistally adjacent a second region within the delivery site withoutremoving the guide cannula from the bone structure; and delivering thecurable material to the second region within the delivery site. Themethod may further include heating the delivery cannula to a secondtemperature to actuate it to a second selected curvature before or afterpositioning the distal end distally adjacent the second region.

In still another aspect, presently disclosed embodiments may relate to amethod of injecting curable material to a delivery site within a bonestructure, where the method may include steps of providing a deliverycannula that includes an open proximal end, a distal segment oppositethe proximal end having a distal tip, a lumen extending from theproximal end; locating a distal tip of a guide cannula within the bonestructure; inserting the delivery cannula within the guide cannula;distally advancing the delivery cannula such that the distal end segmentprojects distal of the guide cannula distal tip, the distal end of thedelivery cannula extending outside of a longitudinal axis substantiallydefined by the guide cannula; heating the delivery cannula to a firsttemperature to actuate it to a first selected curvature; manipulatingthe delivery cannula such that at least a portion of the distal segmentcreates one or more voids in soft body tissue within the bone structure;and delivering the curable material to the delivery site wherein thecurable material is delivered to the one or more voids in the soft bodytissue created by the distal segment. The method may further includeheating the delivery cannula to a second temperature to actuate it to asecond selected curvature, which may be used to create one or morefurther voids.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a furtherunderstanding of the present invention and are incorporated in and are apart of this specification. Other embodiments of the present invention,and many of the intended advantages of the present invention, will bereadily appreciated as they become better understood by reference to thefollowing detailed description. The elements of the drawings are notnecessarily to scale relative to each other, nor do they necessarilyaccurately represent relative scale or proportions of embodimentsdepicted therein. Like reference numerals designate correspondingsimilar parts.

FIG. 1 illustrates components of an intraosseous curable materialdelivery system;

FIG. 2A is a cross-sectional, exploded view of a delivery cannula devicecomponent of the system of FIG. 1;

FIG. 2B is a front view of a delivery cannula and hub portions of thedevice of FIG. 2A;

FIG. 3A is an enlarged plan view of a distal portion of the deliverycannula of FIG. 2A;

FIG. 3B is a cross-sectional view of the delivery cannula of FIG. 3A;

FIG. 4 is a cross-sectional view of the delivery cannula device of FIG.2A upon final assembly;

FIG. 5 is a side plan view of another embodiment of a delivery cannuladevice;

FIG. 6A is a simplified plan view of an intraosseous curable materialdelivery system employed in a palliative bone procedure;

FIG. 6B illustrates a stage of a procedure performed by the system ofFIG. 6A;

FIG. 6C is a transverse, sectional view of a vertebral body incombination with a portion of the system of FIG. 6A, illustratinginjection of curable material after the delivery cannula has been curvedby application of heat thereto to reach a temperature corresponding to adesired curve;

FIG. 6D is a transverse, sectional view of a vertebral body illustratingpossible vertebroplasty approach positions using embodiments disclosedherein;

FIGS. 7A-7C are simplified anterior views of a vertebral body,illustrating use of one device embodiment;

FIGS. 8A and 8B are simplified lateral views of a vertebral body,illustrating use of one device embodiment;

FIG. 9 is a simplified lateral view of a vertebral body, illustratinguse of one device embodiment;

FIGS. 10-10A show a simplified lateral view of a vertebral body,illustrating use of one device embodiment;

FIGS. 11A-11C are simplified anterior views of a vertebral body,illustrating use of one device embodiment; and

FIG. 12 is a simplified anterior view of a sacrum, illustrating use ofthe one device embodiment.

DETAILED DESCRIPTION

FIG. 1 illustrates components of an intraosseous, curable materialdelivery system 20. The system 20 includes an outer guide cannula 22 anda delivery cannula device 26 (referenced generally). Details on thevarious components are provided below. In general terms, however, aportion of the delivery cannula device 26 is sized to be slidablydisposed within the guide cannula 22 that otherwise serves to formand/or locate a desired delivery site within bone. After it ispositioned through the guide cannula lumen, the delivery cannula device26 may be employed to inject a curable, bone stabilizing material intothe delivery site. The system 20 can be used for a number of differentprocedures, including, for example, vertebroplasty and other boneaugmentation procedures in which curable material is delivered to a sitewithin bone, as well as to remove or aspirate material from a sitewithin bone.

The system 20, and in particular the delivery cannula device 26, ishighly useful for delivering a curable material in the form of a bonecement material. The phrase “curable material” within the context of thesubstance that can be delivered by the system/device of the inventiondescribed herein is intended to refer to materials (e.g., composites,polymers, and the like) that have a fluid or flowable state or phase anda hardened, solid or cured state or phase. Curable materials include,but are not limited to injectable polymethylmethacrylate (PMMA) bonecement, which has a flowable state wherein it can be delivered (e.g.,injected) by a cannula to a site and subsequently cures into hardenedcement. Other materials, such as calcium phosphates, bone in-growthmaterial, antibiotics, proteins, etc., could be used in place of or toaugment, PMMA (but do not affect an overriding characteristic of theresultant formulation having a flowable state and a hardened, solid orcured state). This would allow the body to reabsorb the cement orimprove the clinical outcome based on the type of filler implantmaterial. With this in mind, and in one embodiment, the system 20further includes a source (not shown) of curable material fluidlycoupled to the delivery cannula device 26.

Given the above, the outer guide cannula 22 generally enables access ofthe delivery cannula device 26 to a bone site of interest, and thus canassume a wide variety of forms. In general terms, however, the guidecannula 22 is sized to slidably receive a portion of the deliverycannula device 26, terminating in an open, distal tip 28. The distal tip28 can further be adapted to facilitate coring of bone tissue, such aswhen using the guide cannula 22 to form a delivery site within bone. Topromote a desired interface between the guide cannula 22 and a portionof the delivery cannula device 26 otherwise slidably inserted within theguide cannula 22 during use (described below), in one embodiment, aninner diameter surface of the guide cannula 22 is highly smoothed to amatte or mirror finish (i.e., RMS range of about 0-18). In anotherpreferred embodiment, the inner diameter surface of the guide cannula 22or the outer diameter surface of the delivery cannula 36 can be coatedwith, for example, polytetrafluoroethylene (PTFE) or anotherlow-friction or lubricious material to promote a smooth desiredinterface between the guide cannula 22 and a portion of the deliverycannula device 26 otherwise slidably inserted within the guide cannula22 during use. A PTFE sleeve between the guide cannula 22 and a portionof the delivery cannula device 26 may also be used. Further, the outerdiameter surface of the delivery cannula 36 can be polished to a highlysmoothed to a matte or mirror finish (i.e., RMS range of about 0-18).Regardless, and in some embodiments, the guide cannula 22 can further beattached, at a proximal end thereof, to a handle 30 for enhancing asurgeon's ability to manipulate the system 20. Alternatively, the handle30 can be eliminated.

As shown in FIG. 1, the delivery cannula device 26 includes a memorymetal material. The elongate tubular body 36, which may be embodied as avertebroplasty needle or other bone augmentation needle, may beconstructed of—for example—Nitinol and/or another memory metal.Memory-metal materials are well-known in the art. In certainembodiments, the body 36 may generally be formed as a polymeric tubewith one or more lengthwise (linear, curved, spiral, etc.) memory metalsupports. The memory metal supports may be disposed on one or more of aninner surface, an outer surface, and embedded in the wall of thepolymeric tube (which may be, for example, made of PEEK or anothersuitable material with sufficient stiffness—as supported by the memorymetal—to provide the structural and functional features describedherein. As shown in FIG. 1, a cannula body 36 including a memory metalmaterial may be configured to have a generally straight-line body at afirst temperature, such as—for example—a typical ambient temperature,which body generally defines a longitudinal axis. In a polymeric tubebody, the memory metal may provide both structural rigidity needed tooperate in target tissue and the temperature-dependent curvaturepresently disclosed.

The memory metal portion of the body may be configured to provide atleast a first curvature of a distal deflectable length of the cannulabody 36 when heated to a first elevated temperature, a second curvatureat a second elevated temperature, and so on for a plurality oftemperature-dependent curvature states where the deflectable portion iscurved out of the longitudinal axis by a known amount. Thisconfiguration of the memory metal (whether in tube form making up asignificant body portion of the cannula, or as strut(s) or otherstructural elements) may be provided by thermosetting of the memorymetal during manufacture, applying technology known and used in the artof memory metal manufacture.

By way of illustrative example, with reference to FIG. 1, at ambienttemperature, the body 36 is generally straight, and—with reference tothe following table—

At about The curvature of the distal delivery Corresponding to adashed-line this temperature cannula end 82 relative to the curvedorientation in FIG. 1 (e.g., +/−4° C..) longitudinal axis may be about:designated by reference number: 45° C.  30° 82w 55° C.  60° 82x 65° C. 90° 82y 75° C. 120° 82zThese temperatures are examples only. Other curves corresponding toother temperatures may be included. Most preferably, the curvaturedesired may be assumed with a short application of heat to reach thedesired temperature, where the heat and associated temperature arewithin relatively low-risk tolerances for a patient being treated. Asanother example, a temperature of about 60° C. may correspond to acurvature of about 45°, a temperature of about 70° C. may correspond toa curvature of about 90°, and a temperature of about 80° C. maycorrespond to a curvature of about 135°. In another embodiment, ambienttemperature may correspond to a straight cannula, a temperature of about65° C. may correspond to a curvature of about 55°, and a temperature ofabout 80° C. may correspond to a curvature of about 95°. In other words,subject to the physical limitations of the memory metal material, two,three, or more pre-set curves may be used that correspond with selectedtemperatures (where the greater degrees of curvature away from thelongitudinal axis generally correspond to higher temperatures). Thecurves may range from more than 1, but less than about 10 degrees tonearly 180 degrees, with a preferred range of about 20 degrees to about135 degrees.

During a vertebroplasty or other bone augmentation procedure, it may bedesirable to access a location within the bone that is not readilyaccessible through a single-entry (e.g., unipedicular) approach using astraight needle or a delivery cannula available with a particularpre-set curve. Providing a plurality of delivery cannulas with differentpre-set curvatures as part of a surgical kit presents barriers of costand convenience not present in the present system. Additionally, thepresent system's cannula curvature may be adjusted “on the fly” byapplying heat to the cannula sufficient to change the curvature. Thismay be useful if a physician, during a treatment procedure, wishes toaccess a different location within the target delivery site after adelivery cannula is already in place. A multi-needle system wouldrequire swapping out and reloading a new delivery cannula and mostlikely making a new batch of curable bone cement material. With thepresent system, a different curvature may be realized without incurringthe additional time, expense, and risk associated with device exchangeand extended procedural requirements.

The delivery cannula device 26 is shown in greater detail in FIG. 2A,and generally includes a handle assembly 32 (referenced generally), ahub 34, and a delivery cannula 36. The hub port 34 forms a fluid portand is fluidly connected to the delivery cannula 36, with the handleassembly 32 retaining the combination hub 34/delivery cannula 36. Asdescribed in greater detail below, the delivery cannula 36 is sized tobe coaxially, slidably received within the guide cannula 22 (FIG. 1),and is adapted to deliver a curable material injected therein via thehub 34.

The handle assembly 32 includes, in one embodiment, a handle 40 and aretainer 42. The handle 40 is adapted to receive the hub 34, with theretainer 42 securing the hub 34 (and thus the delivery cannula 36) tothe handle 40.

The handle 40, in one embodiment, includes a first section 44 adaptedfor snap-fit assembly to a second section 46, such as by complimentaryannular protrusion(s) 48 and grooves 50. Regardless, the first section44 forms a central passage 52 extending inwardly from an exteriorsurface 54 thereof.

The second section 46 defines an internal aperture 56 that, upon finalassembly of the handle 40, is aligned with the central passage 52. Theaperture 56 can assume a variety of forms sized to receive the hub 34 ina nested manner. The nested interface between the handle 40 and the hub34 is preferably adapted such that the hub 34 cannot rotate relative tothe handle 40 upon final assembly (i.e., the hub 34/handle 40 interfaceresists a torque imparted on either component such that rotationalmovement of the handle 40 results in an identical rotation of the hub34/delivery cannula 36 even when the delivery cannula 36 is insertedwithin a confined surgical site). Thus, in one embodiment, the aperture56 and the hub element 34 (as described below) may have correspondingnon-symmetrical or non-circular shapes in transverse cross-section. Inone embodiment, the second section 46 may include exterior threads 62.Alternatively, the handle assembly 32 can assume a wide variety of otherforms and in some embodiments can be eliminated entirely.

In one embodiment, the hub 34 may include a conventional fluid portdesign and defines a fluid passage 71 and an exterior thread 72 on aproximal end 74 thereof. In one embodiment, the thread 72 is a doublestart right hand Luer thread including a 5-millimeter lead, althoughother thread conformations and lead sizes are also acceptable.Regardless, as previously mentioned, in one embodiment, the hub 34 isconfigured to be rotatably “locked” relative to the handle assembly 32upon final assembly. Thus, in one embodiment, a body of the hub 34 formsa generally cylindrical surface 76 a portion of which is flattened in anarea 78, as shown in FIG. 2B. The size and shape of the flattened area78 corresponds with the aperture sidewall 58 (FIG. 2A) provided with thehandle 40 (FIG. 2A). A removable cap 38 may be provided, adapted toattach to the first section 44 of the handle assembly 32 and cover thefluid passage 71 of the hub 34.

As shown in FIG. 2A, the delivery cannula 36 defines a proximal end 80and a distal end 82, and forms one or more side orifices 84 adjacent thedistal end 80 and in fluid communication with an internal deliverycannula lumen 86. In addition, the delivery cannula 36 includes adeflectable distal segment 88 (referenced generally) defining aplurality of pre-set curves or bends 90 as herein described. Asdescribed below, the deflectable segment 88, and in particular thebend(s) 90, includes or extends from the distal end 82, and has a shapememory attribute. As described above, and shown in FIG. 1, thedeflectable segment 88 may be directed into different curvatures.

The proximal end 80 is axially open to the lumen 86. Conversely, thedistal end 82 is axially closed to the lumen 86, and the distal end 82defines or includes a blunt tip 100. For example, in one embodiment, theblunt tip 100 defines a hemispherical surface, although other blunt(i.e., curved or curvilinear) shapes or contours are also acceptable.

With reference to FIGS. 2A and 2B, the side orifice(s) 84 is formedadjacent the distal end 82, extending through a thickness of a sidewallof the delivery cannula 36. In one embodiment, a single orifice 84 isprovided, and is located generally opposite a direction of the bend 90.In other words, relative to the longitudinal cross-sectional view ofFIG. 2A, a direction of the bend 90 serves to form the delivery cannula36 to define an interior bend side 102 and an exterior bend side 104.The side orifice 84 is formed along, and is open relative to, theexterior bend side 104.

The side orifice(s) 84 can assume a wide variety of shapes and sizes(relative to an exterior surface of the delivery cannula 36). Forexample, the side orifice(s) 84 can be oval, circular, curvilinear, etc.In one embodiment, and with reference to FIG. 3A, a chamfered region 106can be formed about the side orifice 84 to eliminate sharp edges alongan exterior of the delivery catheter 36 as well as to promote consistentflow of curable material from the side orifice 84 (via the expandingorifice size effectuated by the chamfered region 106). With embodimentswhere the side orifice 84 is non-circular, an orifice length L and widthW are defined. To this end, the length L may be greater than 0.050 inch,preferably greater than 0.075 inch, and even more preferably greaterthan 0.100 inch. The side orifice 84 may be characterized as beingrelatively large, especially as compared to conventional bone cementdelivery needles that otherwise provide only an axial orifice or openingat the distal tip.

In particular, and with additional reference to FIG. 3B (otherwiseillustrating a cross-sectional view of the delivery cannula 36 takenthrough the side orifice 84), the delivery cannula 36 defines an insidediameter ID (i.e., a diameter of the lumen 86). The side orifice 84 isfluidly connected to the lumen 86 and extends in a radial fashion. Withthese conventions in mind, in one embodiment, the length L of the sideorifice 84 is greater the inside diameter ID of the delivery cannula 36.As such, at least one linear dimension of the side orifice 84 is largerthan any orifice dimension that could otherwise be achieved were anorifice to be formed at the distal end 82 (i.e., an axially extendingorifice). That is to say, an orifice formed at and by the distal end 82of the delivery cannula 82 (as is conventionally employed in the bonecement delivery needle art) is limited in size (i.e., diameter) by theinside diameter ID of the delivery cannula 36. In contrast, the sideorifice 84 in accordance with principles of the present invention ismuch larger, presenting a distinct advantage when attempting to pass ahigh viscosity liquid (curable material such as bone cement)therethrough.

Returning to FIG. 2A, in one embodiment, the delivery cannula 36 definesa continuous length between its proximal end 80 and its distal end 82,with its deflectable segment 88 including the bend 90, extending alongapproximately 25% of the length from the distal end 82 (where the lengthof the delivery cannula 36 is the length of extension from the hub 34upon final assembly). In other embodiments suited for other surgicalprocedures, the deflectable segment 88, and in particular the bend 90,may extend along between 10%-50% of the length of the delivery cannula36 as measured from the distal end 82. FIG. 4 shows an assembled view ofthe delivery cannula device 26 that was shown in exploded longitudinalsection view of FIG. 2A.

To facilitate delivery of a curable material (e.g., bone cement) into aconfined site within bone (such as with a vertebroplasty procedure), thedeflectable segment 88 can be formed to define the bend 90 at a radiusof curvature R, with the distal tip 100 offset from the longitudinalaxis of the body 36 at a predetermined angle desired for targetingdelivery to a particular site.

Further, to facilitate ready deflection of the deflectable segment 88from the curved shape to a substantially straightened state (such aswhen the delivery cannula 36 is inserted within the outer guide cannula22 (FIG. 1)) and reversion back to the curved shape, the deliverycannula 36, or at least the deflectable segment 88, is formed of a shapememory metal. In one embodiment, the delivery cannula 36 comprisesNitinol™, a known shape memory alloy of nickel (Ni) and titanium (Ti).In one embodiment, the bend 90 is formed in the delivery cannula 36 bydeforming a straight fluid delivery cannula under extreme heat for aprescribed period of time, which pre-sets a curved shape in the deliverycannula 36.

In another embodiment, the pre-set curve or bend 90 is formed in aninitially straight cannula by cold working the straight cannula andapplying a mechanical stress. Cold working permanently locks acrystalline structure (for example, at least a partial martensiticcrystalline structure) in a portion (i.e., the deflectable segment 88)of the cannula, while an unstressed portion remains in, for example, anaustenitic structure.

In addition to Nitinol, other materials exhibiting this shape memorybehavior can be employed, including superelastic or pseudoelastic copperalloys, such as alloys of copper, aluminum, and nickel, and alloys ofcopper, aluminum, and zinc, and alloys of copper and zinc. Regardless,the deflectable segment 88 is formed to be resilient and to assume thedesired radius of curvature R under pre-determined conditions, asdefined. In this manner, after the delivery cannula 36, and inparticular the deflectable segment 88, is oriented a substantiallystraightened shape at a typical ambient temperature (as shown in FIG.1), upon being heated, the deflectable segment 88 “remembers” thepre-set curved shape(s) and reversibly relaxes/returns to a first,second, or further curvature defining a bend 90, as described in detailbelow.

An additional feature of the delivery cannula 36 in accordance with oneembodiment is shown in the plan view of FIG. 1, which includes indicia110 (referenced generally) adjacent the proximal end 80. The indicia 110are indicative of a location of the distal end 82 relative to the distaltip 28 of the guide cannula 22 upon insertion of the delivery cannula 36within the guide cannula 22. For example, the indicia 110 may includefirst, second, and third depth markings 110 a, 110 b, 110 ccorresponding to a set distance of extension from the distal end of theguide cannula. That is, a longitudinal location of the first depthmarking 110 a relative to the distal end 82 (when the delivery cannula36 is in a generally or substantially straightened state) may becommensurate with a length of the guide cannula 22 in combination withthe handle 30 (where provided).

In another preferred embodiment, the present invention includes a probe(not shown) in the form of a wire that can be inserted into the deliverycannula device 26 to remove blockages that may form within the deliverycannula 36. Preferably, the probe has a diameter that is smaller thanthe inner diameter of the delivery cannula 36 to allow material withinthe delivery cannula 36 to flow around the probe as the probe isinserted into the delivery cannula 36. In one preferred embodiment, theprobe is flexible enough to travel through the curvature of the deliverycannula 36, but still rigid enough to remove blockages within thedelivery cannula 36.

Although the delivery cannula device 26 has been described as includingthe delivery cannula 36 otherwise forming one side orifice 84, a varietyof other configurations are also acceptable. For example, two or morecircumferentially aligned side orifices can be provided. Further, FIG. 5illustrates portions of a different embodiment delivery cannula device120. The delivery cannula device 120 includes a delivery cannula 122that extends a length between a proximal end 124 and a distal end 126,and a hub 128 coupled to the proximal end 124. The delivery cannula 122is similar to the delivery cannula 36 (FIG. 2A) described above(including a blunt tip), but forms a series of longitudinally alignedside orifices 130, spaced along a length of the delivery cannula 122,and fluidly connected to an internal lumen (not shown). Further, thedelivery cannula 122 includes a deflectable segment 132 forming aplurality of pre-set temperature-dependent curves along a segment 134,similar to previous embodiments (only one of which is shown in FIG. 5).

A distal-most side orifice 130 a is offset a distance D1 from the distalend 116. Once again, the distance D1 is, in one embodiment, in the rangeof 0.05-0.5 inch, preferably in the range of 0.1-0.25 inch. Alongitudinal spacing between the remaining side orifices 130 proximalthe distal-most side orifice 130 a can vary. Preferably, however, thesecond side orifice 130 b defines a smaller sized opening as compared tothe distal-most side orifice 130 a, and the third side orifice 130 c issmaller than the second side orifice 130 b. This reduction in sideorifice size proximal the distal end 126 promotes consistentdistribution of curable material otherwise being forced through thedelivery cannula 122.

While three of the side orifices 130 are shown, other configurations arealso acceptable. For example, multiple side orifices (i.e., two or morethan three side orifices) can be formed longitudinally along the lengthof the delivery cannula 122, and in addition, the side orifices 130 caninclude more than one longitudinally aligned series of side orifices. Inan exemplary embodiment, the side orifices 130 that are visible in FIG.5 are matched by another column of longitudinally aligned side orificesformed on an opposing side of the delivery cannula 122 (and thereforenot visible in the view of FIG. 5). Aspects of the present inventionprovide for the side orifices 130 to define circular side orifices,non-circular side orifices, or a set of circular and non-circular sideorifices.

As a point of reference, the pre-set curve 134 shown is curved away froma central longitudinal axis C of the delivery cannula 122 such that thecurvature of the pre-set curve 134 is less than the radius of curvatureR of the pre-set curve 90 (FIG. 2A) previously described, thusillustrating another embodiment in accordance with principles of thepresent invention. In addition, while the side orifices 130 are depictedas formed along the pre-set curve 134, in another embodiment at leastone of the side orifices 130 may be formed proximal the pre-set curve134.

Regardless of an exact configuration, the assembled delivery cannuladevice (such as the delivery cannula device 26 of FIG. 4) in accordancewith principles of the present invention is highly useful in performinga wide variety of bone stabilizing procedures as part of an overallcurable material delivery system. To this end, FIG. 6A illustrates anintraosseous curable material delivery system 150 according to oneembodiment of the present invention, employed to perform avertebroplasty procedure. The system 150 includes the outer guidecannula 22, the delivery cannula device 26, a curable material source152 fluidly coupled to the delivery cannula device 26, and a controller154 coupled to at least the curable material source 152.

The curable material source 152 includes, in one embodiment, a canister160 containing a curable material as previously described, and tubing164 extending from the canister 160 to the handle assembly 30 of thedelivery cannula device 26. In this regard, the tubing 164 terminates ata fitting 166 configured to removably attach to the hub 34. Inparticular, the fitting 166 is configured to fit within the passage 52of the handle 40 and removably couple to the hub 34. In one embodiment,the fitting 166 threads onto a Luer thread defined by the hub 34. Inanother embodiment, the fitting 166 snap-fits over the hub 34.Alternatively, a wide variety of other attachment configurations arealso available.

The controller 154 can assume any form known in the art and may becoupled to a curable material source 152. In one example of anembodiment, the controller 154 will control a mass flow and a mass flowrate (i.e., a fluid delivery rate) of curable material from the canister160 to the delivery cannula device 26, as well as a temperature of thedelivery cannula (by providing heat energy calibrated and controlled togenerate a specific desired temperature corresponding to a desiredpre-set curvature). The heat energy may be provided by any number ofmeans known in the art including—by way of illustrativeexample—resistance circuits, RF energy, injection through the cannula ofheated water or other material, ultrasonic energy, or other means. Thecontroller 154 can include a variety of actuators (e.g., switch(es),foot pedal(s), etc.) affording a user the ability to remotely controlliquid flow into the delivery cannula 36 and/or to control temperature(with the latter actuator(s) preferably including indicia correspondingto the temperature and/or curvature desired). Alternatively, manualcontrol can be employed such that the controller 154 can be eliminatedfor use in dispensing curable material.

As shown in FIG. 6A, during a palliative bone procedure such as a boneaugmentation procedure (shown here as a vertebroplasty), with thedelivery cannula 36 partially retracted within, or entirely removedfrom, the outer guide cannula 22, the outer guide cannula 22 is locatedat a desired delivery site within bone. For example, in a vertebroplastyprocedure the outer guide cannula 22 is introduced into a vertebra 180,preferably at a pedicle 182. In this regard, the vertebra 180 includes avertebral body 184 defining a vertebral wall 186 surrounding bodilymaterial (e.g., cancellous bone, blood, marrow, and other soft tissue)188. The pedicle 182 extends from the vertebral body 184 and surrounds avertebral foramen 190. In particular, the pedicle 182 is attachedposteriorly to the vertebral body 184 and together they comprise thevertebrae 180 and form the walls of the vertebral foramen 190. As apoint of reference, the intraosseous system 150 is suitable foraccessing a variety of bone sites. Thus, while a vertebra 180 isillustrated, it is to be understood that other bone sites can beaccessed by the system 150 (i.e., femur, long bones, ribs, sacrum,etc.).

The outer guide cannula 22 forms an access path to a delivery site 192(or forms the delivery site 192) through the pedicle 182 into the bodilymaterial 188. Thus, as illustrated, the outer guide cannula 22 has beendriven through the pedicle 182 via a transpedicular approach. Thetranspedicular approach locates the outer guide cannula 22 between themammillary process and the accessory process of the pedicle 182. In thismanner, the outer guide cannula 22 provides access to the delivery site192 at the open, distal tip 28. With other procedures, the outer guidecannula 22 can similarly perform a coring-like operation, forming anenlarged opening within bone. In one preferred embodiment illustrated inFIG. 6A, the distal tip 28 of the guide cannula 22 is positioned closeto the entrance point into the delivery site 192. As will be explainedin more detail herein, the smaller the projection of the distal tip 28into the delivery site 192 allows for greater access for the deliverycannula 36 to be positioned within the delivery site 192 and delivercurable material to desired locations within the delivery site 192.

After the outer guide cannula 22 has formed, or is otherwise positionedwithin bone at, the desired delivery site 192, the delivery cannula 36is slidably inserted/distally advanced within the outer guide cannula22. It should be appreciated that a stylet, drill, or other instrumentmay be used as known in the art to form a delivery site 192 (e.g.,directed through the guide cannula 22, used to form the site, thenwithdrawn before insertion of the delivery cannula). As illustratedgenerally in FIG. 6A, the distal end 82 of the delivery cannula 36 ispoised at the distal tip 28 of the outer guide cannula 22. Approximatealignment of the first depth marking 110 a with the handle 30 provides auser with visual confirmation (at a point outside of the patient) of thedistal end 82 positioning relative to the outer guide cannula 22 distaltip 28. Prior to further distal movement, the delivery cannula 36 isentirely within the outer guide cannula 22 with the deflectable segment88 (FIG. 2A) of the delivery cannula 36 in a substantially straightenedshape that generally conforms to a shape of the outer guide cannula 22.

The delivery cannula device 26, and in particular the delivery cannula36, is then distally advanced within the guide cannula 22 as shown inFIG. 6B. In particular, the delivery cannula 36 is distally maneuveredsuch that at least a portion of the deflectable segment 88 extendsbeyond the open tip 28 of the guide cannula 22 and into the deliverysite 192. The deflectable segment 88 may be actuated to deflect to adesired pre-set first, second, or other curvature upon exiting the guidecatheter 22, assuming the pre-set curvature of the bend 90 describedabove due to the shape memory characteristic being activated byapplication of heat energy to heat the needle to a correspondingtemperature as described above. The user can visually confirm a lengthof distal extension of the delivery catheter 36 from the guide catheter22 via a longitudinal positioning of the indicia 110 b or 110 c (theindicia 110 c being visible in FIG. 6B) relative to the handle 30.Further, the directional indicia 114 indicate to a user (at a pointoutside of the patient) a spatial direction of the bend 90 that may beassumed within the delivery site 192 relative to a spatial position ofthe handle 40.

The blunt tip 100 of the distal end 82 is hemispherically shaped (orother non-sharpened or blunt shape) and thus atraumatic relative tocontacted tissue/bone. As such, the blunt tip 100 can contact and/orprobe the vertebral wall 186 with a minimum of risk in puncturing orcoring the vertebral body 184. Thus, the blunt tip 100 offers anadvantage over the conventional, sharp-edged bone cement deliveryneedles. The side orifice 84 is offset from the distal end 82 and is,therefore, available to deliver curable material into, and remove bodilymaterial from, the delivery site 192. In particular, the side orifice 84can eject curable material radially from, and aspirate bodily materialinto, the delivery cannula 36, even when the distal end 82 is pressedagainst a surface, such as an interior wall of the vertebral body 184.

With the above in mind, in one embodiment, the fluid source 152 may thenbe operated (e.g., via the controller 154) to deliver a curable material(not shown) to the delivery cannula 36 via the hub 34. Curable materialentering the delivery cannula 36 is forced through the lumen 86 (FIG.2A) towards the side orifice 84. As shown in FIG. 6D, the curablematerial is then dispensed/injected from the delivery cannula 36 in aradial fashion from the side orifice(s) 84 and into the delivery site192 in a cloud-like pattern 194. Alternatively or in addition, thedelivery site 192 can be aspirated by replacing the curable materialsource 152 (FIG. 6A) with a vacuum source (not shown).

In another embodiment, curable material is preloaded in the deliverycannula. That is, the curable material delivered to the delivery cannula36 before introducing the delivery cannula 36 into the guide cannula 22.In practice, an operator may advance curable material beyond the sideorifice(s) 84 the delivery cannula 36 in order to completely fill thedelivery cannula 36 and then wipe the side orifice(s) 84 of excesscurable material before insertion into the guide cannula 22. Thedelivery cannula 36 is thus preloaded with curable material before thedelivery cannula 36 is connected with the guide cannula 22. After thedelivery cannula 36 is inserted into the guide cannula 22 curablematerial is immediately available to be delivered into the implantationsite. This preloading step advantageously reduces the time required todeliver curable material into a patient because it can be done atsubstantially the same time the guide cannula 22 has being driven intothe delivery site.

Importantly, by injecting the curable material radially from a side ofthe delivery cannula 36 rather than axially from the distal most end (aswill otherwise occur with conventional delivery needles), the system 150(FIG. 6A) can avoid forcing the curable material into a fracture orother defect that may in turn lead to undesirable leaking of the curablematerial through the fracture. By way of example, FIG. 6C illustrates afracture 196 in the vertebral body wall 186. Vertebroplasty is a commonsolution to such vertebral fractures, with the accepted repair techniqueentailing positioning the distal end 82 at or “facing” the fracture 196to ensure that the curable material is dispensed in relatively closeproximity thereto. With known delivery needles, this preferred approachresults in the curable material being injected directly toward thefracture 196. In contrast, with the delivery catheter 36 of the presentinvention, the distal end 82 is still “facing” or at least very near thefracture 196, yet the injected curable material cloud 194 is not forceddirectly toward the fracture 196. Instead, the curable material cloud194 indirectly reaches the fracture 196 with minimal retained propulsionforce such that the curable material cloud 194 is unlikely to forciblyleak through the fracture 196. However, the delivery site 192 is, as awhole, still filled with the curable material cloud 194 to effectuatethe desired repair.

As shown in FIG. 6C, an entirety of the delivery site 192 is accessibleby the delivery cannula 36. To this end, while the guide cannula 22 hasbeen inserted via a right posterior-lateral approach, the system 150 caneffectuate a vertebroplasty procedure from a left posterior lateralapproach, or to right or left anterior lateral approaches as shown inFIG. 6D (which shows two approaches, that could be used together, or inthe alternative.

In more general terms, during the palliative bone procedure, a clinicianoperating the intraosseous system 150 extends the deflectable end lengthof the cannula body 36 into the delivery site 192 otherwise definedwithin bone. In one embodiment, a subsequent rotation of the deliverycannula 36 rotates a spatial position of the side orifice 84 relative tothe delivery site 192, thus accessing multiple planes of the deliverysite 192 with only one “stick” of the outer guide cannula 22. Thus, by acombination of retracting the delivery cannula 36 within the outer guidecannula 22, distally advancing the delivery cannula 36 relative to theouter guide cannula 22, by rotating the delivery cannula 36, and byactuating the cannula to a different curvature by providing thecorresponding heat/temperature, multiple planes and multiple regions ofthe bone site of interest can be accessed by the delivery cannula 36with a single approach of the outer guide cannula 22. Thus, for example,a unipedicular vertebroplasty can be accomplished with the system 150.FIGS. 7A-8B generally illustrate (FIGS. 7A-7C from an anteriorperspective using three different curvatures; FIGS. 8A and 8B from aleft lateral perspective) various planes/regions of the vertebral body182 accessible with rotation and/or advancement of the delivery cannula36 relative to the guide cannula 22, including with changing curvatures(again with the guide cannula 22 remaining stationary). Notably, in thedrawings of FIGS. 7A-8B, a direction of the bend defined by the deliverycannula 36 is not necessarily perpendicular to the plane of the page,such that the bend may not be fully evident in each view.

With reference to FIGS. 9-10, another preferred method for deliveringcurable material is depicted. In this preferred embodiment, a cliniciancreates voids 210 in soft body material 200 (e.g., cancellous bone,blood, marrow, and other soft tissue) within a bone delivery site bymanipulating the curved end 90 of the delivery cannula 36. The voids 210can then be filled with curable material. It has been observed that whenvoids are created, curable material delivered to the delivery site willgenerally flow into the voids 210 instead of the soft body material 200.As a result, a clinician can create a void 210 at a relatively smalldesired area, and fill primarily just that area with curable material.

According to one preferred embodiment, voids can be created through acombination of retracting the delivery cannula 36 within the outer guidecannula 22 and distally advancing the delivery cannula 36 relative tothe outer guide cannula 22, thus moving the curved end 90 in areciprocating manner. The reciprocating action causes the curved end 90to crush the soft body tissue and create a channel 212 within the softbody material. Additionally, by retracting the delivery cannula 36within the outer guide cannula 22 and rotating the delivery cannula 36so that the curved end 90 will distally advance within the delivery siteat a different orientation, the curved end 90 can create multiplechannels 212 within the soft body tissue 200. Further, the curved end 90of delivery cannula 36 may be advanced distally only partially withinthe delivery site and then removed to create shorter channels 212 withinthe implantation site where desired. Actuating the different curvaturesof the presently-disclosed delivery cannula may enable formation of agreater variety and/or number of voids than previously available via asingle guide cannula without the disadvantages associated withexchanging out a delivery cannula for one with a different neededcurvature, or having to settle for a different injection site thandesired.

According another preferred embodiment shown in FIG. 10, the deliverycannula 36 can be rotated or spun after the curved end 90 has beenintroduced into the implantation site. The rotating or spinning of thedelivery cannula 36 causes the curved end 90 to rotate through bodytissue 200 to create a cone-shaped void 214 in the soft tissue 200within the delivery site. As shown in FIG. 10A cone-shaped voids 214 ofdifferent sizes and locations may be created by inserting the curved end90 into the implantation site by less than its full length and/or atdifferent actuated curvatures and, thereafter, rotating the deliverycannula 36. If it is desirable to insert the delivery cannula 36 throughthe guide cannula by less than its full length, it may be advantageousto use one or more spacers such as those disclosed in U.S. Pat. No.8,128,633, which is incorporated herein by reference in its entirety.

Voids 210 within the soft body tissue of various sizes and shapes can becreated by using a combination of the above disclosed methods. Accordingto one preferred method, a physician may introduce curable materialwithin the implantation site as he or she is creating the voids withinthe implantation site. Thus, the voids may be created and filled at thesame time. One skilled in the art will appreciate that whether voids arefirst created and then filled, or curable material may be delivered in acloud-like pattern through the existing intravertebral tissue withoutfirst creating voids, the delivery cannula of the present invention canbe manipulated to deliver small deposits of curable material to specificdesired areas within a cavity.

In one embodiment, curable material can be delivered in different planesto form curable material structures within the cavity to stabilize theendplates of a vertebral body 180, as depicted in vertical transversesection in FIGS. 11A and 11B. The vertebral body 180 will, in mosttreatment scenarios, have a degraded physiology not shown here,including one or more of vertical compression, structural disruption ofone or more walls (e.g., endplates, lateral walls). In one preferredembodiment, curable material 232 a and 232 b is deposited in contactagainst the endplates 230 a and 230 b of the vertebral body so that thecurable material substantially interfaces with the endplates 230 a and230 b and provides structural support. According to one preferredembodiment, the procedure leaves a region between the curable materialdeposits 232 a and 232 b that contains substantially no curablematerial. Curable material can thus be deposited in only a particularregion or regions of the cavity. Physician desired localization of thesedeposits can be facilitated by the multi-curve device presentlydisclosed. For example, a physician may determine that a first depositmay best be achieved at a first curvature corresponding to a firsttemperature, a second deposit may best be achieved at a second curvaturecorresponding to a second temperature, etc. (for two or more desiredcurvatures and locations).

With reference to FIG. 11C, in another preferred embodiment the curablematerial deposits 232 a and 232 b can be connected by placing curablematerial between the curable material deposits 232 a and 232 b to form acurable material stabilizing column 234. In this embodiment, curablematerial deposits 232 a and 232 b are first created to stabilize theendplates of the vertebral body. A stabilizing curable material column234 is then created between the curable material deposits 232 a and 232b to connect the curable material deposits and form a curable materialstructure within the vertebral body. By first stabilizing the endplates, deformities created due to compression fractures can bestabilized. By stabilizing both end plates and then creating a columntype structure between the end plates, the vertebral body stiffness maybe significantly improved thereby minimizing issues of the overallstrength of the vertebral body. Some reduced vertebral height may evenbe recovered or at least not allowed significant further progressthereby. Further, a physician may be able to exploit the multi-curvestructure and function of the delivery cannula to help optimize locationof the three deposits. For example, the first deposit 232 a may best beplaced using a first curvature corresponding to a first temperature, thesecond deposit 232 b may best be placed using the same first curvature,and the intervening curable material column 234 may best be placed usinga second curvature, reached by heating the needle to a secondtemperature.

With reference to FIG. 12, another preferred method for deliveringcurable material is depicted. In this preferred embodiment, the deliverysite is the sacrum 220, shown in horizontal transverse section. In thisembodiment, curable material is delivered to the sacrum 220 to repairbone fragments or fractures in the sacrum. According to one preferredmethod of the present invention, curable material is delivered tomultiple regions within the sacrum through a single access point.Preferably, a guide cannula 22 is inserted generally at the middleportion of the sacrum. As has been described above, a curvable needle isinserted into and advanced relative to the guide cannula 22. Thedelivery cannula 36 is preferably oriented so the curvable end 90 entersproximal to a first region 221 of the sacrum 220 after being heated to afirst temperature corresponding to a first curvature shown in solid line(as “A”). Curable material is then delivered to the first region 221 ofthe sacrum 220. After curable material is delivered to the first region221, the physician can then partially or fully retract the curved end 90within the guide cannula and then re-orient the delivery cannula 36 andcurved end 90. As the delivery cannula 36 is again advanced relative tothe guide cannula 22, the curved end 90 enters proximal to a secondregion 222 within the sacrum 220. Curable material is then delivered tothe second region 222 of the sacrum 220 using the same curvature (shownin dashed-line as “B”). The process can be repeated for other additionalregions, such as—for example—retracting the delivery cannula 36 justinto the delivery cannula, heating it to a second temperaturecorresponding to a second curvature and re-introducing it (intodashed-line position “C”). It should be appreciated that theretracting/heating method may be used in other embodiments as well(e.g., rather than increasing heat to change curvature while the cannula36 is extended within the bone). Although the implantation sitedescribed above is the sacrum, fractures in other bones can be repairedby delivering curable material to multiple regions through the sameaccess point using the above described methods

Although specific embodiments have been illustrated and describedherein, it will be appreciated by those of ordinary skill in the artthat a variety of alternate and/or equivalent implementations may besubstituted for the specific embodiments shown and described withoutdeparting from the scope of the present invention. This application isintended to cover any adaptations or variations of the specificembodiments discussed herein. Therefore, it is intended that thisinvention be limited only by the claims and the equivalents thereof. Forexample, while specific reference has been made to vertebroplastyprocedures, the devices, systems, and methods in accordance withprinciples of the present invention are equally applicable to deliveringcurable material within multiple other bones of a patient.

Those of skill in the art will appreciate that embodiments not expresslyillustrated herein may be practiced within the scope of the presentinvention, including that features described herein for differentembodiments may be combined with each other and/or with currently-knownor future-developed technologies while remaining within the scope of theclaims presented here. It is therefore intended that the foregoingdetailed description be regarded as illustrative rather than limiting.And, it should be understood that the following claims, including allequivalents, are intended to define the spirit and scope of thisinvention.

What is claimed is:
 1. A system for augmenting a bone structure, thesystem comprising: a shape memory device comprising a length definedbetween a proximal end opposite a distal end, a proximal segmentdefining a straight longitudinal axis, and a deflectable distal segmentincluding temperature-dependent memory metal material; and a guidecannula having a guide cannula lumen configured to slidably receive saidshape memory device, wherein said deflectable distal segment isconfigured to form a first deflected shape having a first bend away fromsaid straight longitudinal axis at a first elevated temperature greaterthan an initial temperature at which said deflectable distal segment isin a substantially longitudinally straightened form, and form a seconddeflected shape having a second bend away from said straightlongitudinal axis at a second elevated temperature greater than saidfirst elevated temperature.
 2. The system of claim 1, wherein saiddeflectable distal segment has a shape memory characteristic such thatsaid deflectable distal segment is configured to assume a substantiallystraightened form generally along said longitudinal axis when subjectedto a force from said guide cannula lumen and naturally revert to one ofsaid first deflected shape, said second deflected shape, and anotherdeflected shape upon removal of the force.
 3. The system of claim 1,wherein said deflectable distal segment is deflectable from said firstdeflected shape to said second deflected shape without removing saiddeflectable distal segment from the bone structure.
 4. The system ofclaim 1, wherein said shape memory device further comprises depthindicia on said proximal segment with said depth indicia indicative of alocation of said distal end of said shape memory device relative to adistal tip of said guide cannula.
 5. The system of claim 1, wherein saidshape memory device further comprises a handle defining said proximalend with said handle having directional indicia indicative of a bendingdirection of said distal end of said shape memory device relative to anorientation of said handle.
 6. The system of claim 1, wherein saiddeflectable distal segment of said shape memory device is configured tobe manipulated within the bone structure to create voids fillable withcurable material.
 7. The system of claim 1, wherein the deflectabledistal segment extends between 10% and 50% of said length of said shapememory device as measured from said distal end.
 8. A method forpositioning a shape memory device within a bone structure with the shapememory device comprising a length defined between a proximal endopposite a distal end, a proximal segment defining a straightlongitudinal axis, and a deflectable distal segment including memorymetal material that is temperature-dependent, the method comprising:locating a distal tip of a guide cannula within the bone structure;inserting the shape memory device within the guide cannula such that thedeflectable distal segment assumes a substantially straightened formgenerally along the straight longitudinal axis when subjected to a forcefrom the guide cannula; advancing the deflectable distal segment beyondthe distal tip of the guide cannula and within the bone structure;heating the deflectable distal segment to a first elevated temperaturegreater than an initial temperature at which said deflectable distalsegment is in the substantially straightened form such that saiddeflectable distal segment forms a first curved shape having a firstdegree of curvature away from said straight longitudinal axis; andwithout removing the deflectable distal segment from the bone structure,further heating the deflectable distal segment to a second elevatedtemperature greater than the first elevated temperature such that thedeflectable distal segment forms a second curved shape having a seconddegree of curvature away from the straight longitudinal axis greaterthan the first curved shape.
 9. The method of claim 8, wherein the stepof heating the deflectable distal segment to the first elevatedtemperature is performed to form the first curved shape to thedeflectable distal segment upon exiting the guide cannula.
 10. Themethod of claim 8, wherein the deflectable distal segment naturallyreverts to one of the first curved shape, the second curved shape, andanother curved shape upon removal of the force from the guide cannula.11. The method of claim 8, further comprising manipulating the shapememory device such that the deflectable distal segment creates voidswithin the bone structure.
 12. The method of claim 11, wherein the stepof manipulating further comprises moving the shape memory device in areciprocating manner.
 13. The method of claim 11, wherein the step ofmanipulating further comprises rotating the shape memory device aboutthe straight longitudinal axis.
 14. The method of claim 9, furthercomprising providing energy to move the deflectable distal segment fromthe second curved shape towards the first curved shape, and removing thedeflectable distal segment from the guide cannula.
 15. A method forpositioning a shape memory device within a bone structure with the shapememory device comprising a length defined between a proximal endopposite a distal end, a proximal segment defining a straightlongitudinal axis, and a deflectable distal segment including memorymetal material that is temperature-dependent, the method comprising:locating a distal tip of a guide cannula within the bone structure;inserting the shape memory device within the guide cannula such that thedeflectable distal segment assumes a substantially straightened formgenerally along the straight longitudinal axis when subjected to a forcefrom the guide cannula; and advancing the deflectable distal segmentbeyond the distal tip of the guide cannula and within the bonestructure; heating the deflectable distal segment to a first elevatedtemperature greater than an initial temperature at which saiddeflectable distal segment is in the substantially straightened formgenerally along the straight longitudinal axis to deflect the distal endof the deflectable distal segment to a first target region within thebone structure; and without removing the deflectable distal segment fromthe bone structure, further heating the deflectable distal segment to asecond elevated temperature greater than the first elevated temperatureto deflect the distal end of the deflectable distal segment to a secondtarget region within the bone structure.
 16. The method of claim 15,further comprising manipulating the shape memory device such that thedeflectable distal segment creates voids within the bone structure atone of the first or second target regions.
 17. The method of claim 16,wherein the distal segment terminates in a closed end and the shapememory device further comprises a side orifice.
 18. The method of claim17, further comprising the step of preloading the shape memory devicewith curable material prior to inserting the shape memory device intothe guide cannula.